Field of the Invention
This invention relates in general to a coolant delivery system for a high speed dental cutting handpiece, and in particular to a coolant delivery system wherein coolant delivery ceases substantially immediately with cessation of handpiece cutting action.
The use of high speed dental handpieces such as drills employed in preparing teeth for fillings and the like requires that this equipment be kept at a reasonable temperature while in the mouth of a patient. Because of the high speed of a drill, for instance, heat generated by friction as the drill contacts a tooth could easily burn tissue in the mouth. To alleviate this problem, handpieces usually have a coolant spray or mist, which is generally water, that encompasses the work area and is emitted from the distal end of the handpiece.
One problem which can occur in such an apparatus is that of backflow of saliva, blood and the like from the mouth of the patient into the reservoir which houses the coolant. As described in U.S. Pat. Nos. 4,470,812 and 4,973,247, incorporated herein by reference, such an event can result in contamination of the coolant and subsequent transfer of these untoward materials to other patients. As taught in these two patents, disposable or sterilizable reservoir containers can aid in the prevention of this condition. A second problem which can occur is that of excess coolant flow after a handpiece is deactivated. Such a condition results in a poor work field, inconvenience for the dentist, and discomfort for the patient.
It is therefore a primary object of the present invention to provide a coolant delivery system wherein coolant delivery occurs substantially only when the handpiece is operational.
Another object of the present invention is to provide a coolant delivery system wherein gas pressure which operates a dental handpiece also operates simultaneous coolant delivery.
These and other objects of the present invention will become apparent throughout the description which now follows.